POTATO CO-PRODUCT IN DIETS FOR GROWING AND FINISHING STEER DIETS Vern Anderson and Eric Bock Carrington Research Extension Center North Dakota State University Abstract Potato co-product from AVIKO LLC in Jamestown ND was fed to growing steers during the winter and through finishing to test effects of high moisture potato diets in feedlot cattle. The 82% moisture product was added at 0, 10, 20, and 30% (dry matter basis) of the diet replacing corn as an energy source. Growing diets were about 65% concentrate and finishing diets were 85% concentrate. Feed intake, gain, feed efficiency, and carcass traits were not different but cost of gain decreased with increasing potato co-product given the prices of commodities in this study. Potato co-product makes an excellent feed for growing and finishing steers when used in a balanced ration when priced competitively. Introduction The North Dakota potato industry has developed to a point where the disposal of its coproducts is a serious problem. The disposal options are: landfill, land application, or utilize as a livestock feed ingredient. Potato co-products contain substantial amounts of energy in the form of starch, and are generally low in fiber and protein. Ruminant livestock have the capacity to consume relatively large amounts of potato co-product in a variety of forms and moisture levels. The greatest liability for potato co-products is the high moisture content. This limits the hauling distance and may affect animal intake and/or performance during periods of cold weather. Current potato peeling methods employ steam versus the previously used alkali peeling method, which may have yield a nutritionally different feed product. With the potential for increasing amounts of potato waste and a growing feeding industry in North Dakota, research trials were conducted to evaluate this co-product in growing and finishing diets. This project is one component of a comprehensive potato co-product research study involving products from Simplot at Grand Forks, AVIKO, at Jamestown, and faculty and graduate students from NDSU Animal Science Department. Materials and Methods One hundred-twenty steers were received and preconditioned together at the Carrington Research Center in the fall of 2000. At the start of the trial in December, steers were weighed and allotted to one of four treatments with three replicates per treatment and 10 head per pen. The diet treatments were potato co-product fed at 0%, 10%, 20%, or 30% of the diet dry matter. The potato co-product consisted of approximately equal amounts of three different by-products which were rejected fries, filter cake, and peelings.
Steers were fed a growing diet with a concentrate to roughage ratio of 65:35 for 55 days, followed by a finishing diet with a concentrate to roughage ratio of 85:15 for 84 days. Diets were formulated to meet the nutrient requirements of growing and finishing steers gaining approximately 3.0 and 3.5 pounds respectively. Steers were fed to appetite once daily in a fenceline bunk. Synovex S was implanted in all steers at the start of the trial. An ionophore and supplemental calcium were included in the supplement. Steers were weighed every 28 days. Carcass data was collected after a 24-hour chill. Table 1. Diets for steers fed potato co-product during growing and finishing Item 0% Potato 10% Potato 20% Potato 30% Potato ------------------------Dry matter basis, lb/hd/day---------------------- Growing Corn 9.22 8.25 5.26 2.73 Midds 3.9 3.81 3.87 3.77 Potato co-product 0 2.78 4.77 6.88 Straw 2.81 2.80 2.66 2.59 Alfalfa 2.78 2.78 2.76 2.78 Canola Meal.89.89.89.89 Supplement.54.54.54.54 Finishing Corn 15.06 12.14 9.53 6.46 Midds 5.28 5.14 5.15 5.07 Potato co-product 0.00 2.92 5.71 8.34 Straw 2.66 2.42 2.42 2.39 Alfalfa 1.79 1.75 1.76 1.65 Canola Meal 0.96 0.97 0.97 0.97 Supplement.54.54.54.54
Table 2. Performance of steers fed potato by-product at 0%, 10%, 20%, or 30% of diet dry matter Item 0% Potato 10% Potato 20% Potato 30% Potato SE P value Number head 30 30 30 30 Growing Initial weight, lbs. 783.07 787.97 786.03 790.07 9.96.97 DMI, lbs. 20.48 a 21.08 b 20.74 c 20.14 d.01.01 ADG, lbs. 3.37 3.64 3.74 3.53.13.25 F/G, lbs. 6.09 5.80 5.50 5.72.12.07 Cost/lb. gain a, $.214.197.174.167 Finishing Final weight, lbs. 1272.89 1265.60 1255.53 1263.30 14.87.88 DMI, lbs. 26.26 25.84 26.03 25.61.17.10 ADG, lbs. 3.62 a 3.30 b 3.14 b 3.32 b.09.01* F/G, lbs. 7.31 7.84 8.30 7.71.25.11 Cost/lb. gain a, $.260.267.264.229 Overall DMI, lbs. 23.95 a 23.94 a 23.91 a 23.42 b.10.01 ADG, lbs. 3.52 3.44 3.38 3.40.08.56 F/G, lbs. 6.83 6.98 7.08 6.88.17.74 Cost/lb. gain, $**.242.235.225.200 * Linear and quadratic effects (P<.10) **Ingredient costs- Rumensin: $300/ton, Mineral: $320/ton, Limestone: $100/ton, Wheat Midds: $60/ton, Corn: $1.70/bu., Canola Meal: $100/ton, Straw: $25/ton, Alfalfa: $50/ton, Potato co-product: $7.50/ton a,b,c,d Values with different superscripts are significantly different (P<.05) Table 3. Carcass traits of steers fed potato co-product during growing and finishing Item 0% Potato 10% Potato 20% Potato 30% Potato SE P value Hot Carcass Wt, lb. 769.24 774.48 769.77 768.48 9.54.97 Dressing Percent 60.45 60.94 61.31 60.94.30.12 Marbling Score* 479 498 499 531 19.81.32 Fat Thickness, in.49.50.48.53.03.70 Rib Eye Area, sq in 13.36 13.41 13.24 13.05.22.67 KPH, % 2.20 2.12 2.08 2.19.04.13 Yield Grade 3.23 3.25 3.22 3.33.07.70 *Score indicates quality grade with 400+ = low choice and 500+ = average choice
Results and Discussion Steers performed equally and satisfactorily during the entire feeding period on all diets. The only significant difference (P<.05) in overall performance was in dry matter intake. The steers fed 30% potato co-product consumed approximately 0.5 lbs. less per day than the other three treatments (Table 2). However, no differences (P>.05) were observed in daily gain or feed efficiency. There were differences between feeding periods as the steers fed 10%, 20%, and 30% potato co-product tended to gain more during the growing period, while the steers fed 0% co-product had the performance advantage (P<.05) in the finishing period. The finish period gain differences were linear and quadratically significant (P<.10). There appears to be no interaction of cold and moisture content of the diet. The growing diet was fed during December, January, and February. The heat increment of forage may have offset any extra energy required to warm the moist diet. Finishing diets performed in an opposing pattern with the potato co-product diets providing lower gains. With dry matter intake essentially the same, the variability of the potato co-product or simply the lower energy density of potato co-products may be partially responsible for changes in gain. With reported feed prices, the cost per lb. of gain was $0.042/lb less when potato coproduct was fed at 30% versus 0%. This amounts to approximately $20/hd over the duration of the trial. There were no significant differences (P>.05) in carcass characteristics (Table 3). Potato co-product is a palatable and economical energy source in both growing and finishing diets. Moisture level does not appear to be a critical factor at the levels imposed in this trial. Feeders who use potato co-product should sample the feed periodically for nutrients as there can be some variation based on amount of peel, filter cake, or fries present. Cattle generally relish the feed and it provides dust control from added moisture. It can be fed fresh, with timely deliveries from the processing plant. Periodic shutdowns for maintenance or cleaning can interfere with availability. Potato waste can also be ensiled during the summer when large amounts are available and fed during the winter. Cost equivalency for potato co-product at the various levels fed was calculated using respective cattle performance over the entire feeding period. Table 4 provides a matrix of breakeven costs for potato waste to corn at a range of corn prices and at the dietary levels of potato co-product fed in the study. Implications Potato co-products are limited in their use by transportation costs which amount to approximately $1 per ton for every 10 miles hauled from the AVIKO plant near Jamestown, ND. For feeders within a reasonable radius, using potato waste in growing and finishing diets can lower the cost of gain without sacrificing performance. Breakeven pricing or marketing at equivalent value will not attract feeders to use potato co-product. Feeders are motivated by profit so a programmed discounting system may be the best approach i.e. potato co-product is offered for sale at an agreed upon percentage of the breakeven price based on average cash corn prices. Resistance to using the feedstuff comes in the form of logistics and delivery scheduling, shrinkage from moisture
loss during trucking and storage, certain odors that accompany the product, and attraction of flies and insects in the feeding area. The product can be variable in composition and non-homogenous in consistency with differing proportions of rejected fries, peeling, and filter cake. In spite of these factors, economic opportunity for profit by feeding potato co-product exists. Table 4. Equivalent value of potato by-product when replacing corn at 10%, 20%, and 30% of diet dry matter in feedlot rations. Amount of Potato Co-product in diet Feed cost/lb Price of Corn $/bu. gain with 0% Potato 10% Potato 20% Potato 30% Potato $1.50 $0.211 $9.43 $9.66 $12.93 $1.75 $0.227 $10.72 $11.32 $14.86 $2.00 $0.243 $12.01 $12.93 $16.70 $2.25 $0.259 $13.57 $14.58 $18.68 $2.50 $0.275 $14.93 $16.33 $ 20.61